Part architectural guidebook and part critique, Sky-High documents the pencil-thin, supertall towers that are transforming New York City's skyline as well as its streets.New York City's penchant for building skyward has reached new heights with its crop of supertall towers—those that rise at least 984 feet above the sidewalk. The city that never sleeps is also the city that never stops building ever higher, from the Woolworth and Chrysler buildings of an e...